scholarly journals Root-Derived Proteases as a Plant Tool to Access Soil Organic Nitrogen; Current Stage of Knowledge and Controversies

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 731
Author(s):  
Bartosz Adamczyk
Keyword(s):  
Cropping Systems ◽  
N Uptake ◽  
Organic N ◽  
Inorganic N ◽  
Available N ◽  
Plant Nitrogen ◽  
N Cycle ◽  
Soil Organic Nitrogen ◽  
Use Efficiency ◽  
N Pool

Anthropogenic deterioration of the global nitrogen (N) cycle emerges mainly from overuse of inorganic N fertilizers in nutrient-limited cropping systems. To counteract a further dysregulation of the N cycle, we need to improve plant nitrogen use efficiency. This aim may be reached via unravelling all plant mechanisms to access soil N, with special attention to the dominating high-molecular-mass N pool. Traditionally, we believe that inorganic N is the only plant-available N pool, however, more recent studies point to acquisition of organic N compounds, i.e., amino acids, short peptides, and proteins. The least known mechanism of plants to increase the N uptake is a direct increase of soil proteolysis via root-derived proteases. This paper provides a review of the knowledge about root-derived proteases and also controversies behind this phenomenon.

scholarly journals Targeting Nitrogen Metabolism and Transport Processes to Improve Plant Nitrogen Use Efficiency

2021 ◽  
Vol 11 ◽  
Author(s):  
Samantha Vivia The ◽  
Rachel Snyder ◽  
Mechthild Tegeder
Keyword(s):  
Amino Acids ◽  
Cropping Systems ◽  
N Uptake ◽  
Transport Processes ◽  
N Use Efficiency ◽  
Plant Performance ◽  
Available N ◽  
Plant Nitrogen ◽  
Use Efficiency ◽  
N Use

In agricultural cropping systems, relatively large amounts of nitrogen (N) are applied for plant growth and development, and to achieve high yields. However, with increasing N application, plant N use efficiency generally decreases, which results in losses of N into the environment and subsequently detrimental consequences for both ecosystems and human health. A strategy for reducing N input and environmental losses while maintaining or increasing plant performance is the development of crops that effectively obtain, distribute, and utilize the available N. Generally, N is acquired from the soil in the inorganic forms of nitrate or ammonium and assimilated in roots or leaves as amino acids. The amino acids may be used within the source organs, but they are also the principal N compounds transported from source to sink in support of metabolism and growth. N uptake, synthesis of amino acids, and their partitioning within sources and toward sinks, as well as N utilization within sinks represent potential bottlenecks in the effective use of N for vegetative and reproductive growth. This review addresses recent discoveries in N metabolism and transport and their relevance for improving N use efficiency under high and low N conditions.

Nitrogen dynamics in soil amended with composted cattle manure

2007 ◽  
Vol 87 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Bobbi L Helgason ◽  
Francis J Larney ◽  
H. Henry Janzen ◽  
Barry M Olson
Keyword(s):  
N Uptake ◽  
Wood Chip ◽  
N Fertilizer ◽  
Organic N ◽  
Inorganic N ◽  
Available Nitrogen ◽  
N Content ◽  
Total N ◽  
Available N ◽  
Plant Available Nitrogen

The amount and pattern of plant-available nitrogen (N) release from composts are variable and not well-defined. We used a 425-d canola (Brassica napus L.) bioassay to follow the release of N from eight composted cattle manures applied to soil at 20 g kg-1. Two stockpiled manures, one inorganic fertilizer and an unamended control were also included for comparison. Eight consecutive 30-d growth cycles were conducted in a controlled environment chamber (20°C) and plant N uptake was measured. Total N uptake was greatest from the N fertilizer and least from the wood-chip bedded manure. Addition of compost increased N uptake by 27–99% compared with that in the control. Nitrogen uptake from compost was directly proportional to its inorganic N content (r2 = 0.98; P < 0.0001) showing that the initial inorganic N content of compost, analyzed prior to its application can be used to predict plant available N. In seven of the eight composts studied, less than 5% of organic N was mineralized over 425 d, suggesting that little of the organic N in compost becomes available in the year of application. Compost is a valuable organic amendment, but co-application of N fertilizer is recommended to supply adequate N and optimize the benefits of compost for crop growth. Key words: Plant-available nitrogen, compost, nitrogen mineralization, beef manure

scholarly journals Rice NIN-LIKE PROTEIN 4 is a master regulator of nitrogen use efficiency

2020 ◽  
Author(s):  
Jie Wu ◽  
Zi-Sheng Zhang ◽  
Jing-Qiu Xia ◽  
Alamin Alfatih ◽  
Ying Song ◽  
...  
Keyword(s):  
N Uptake ◽  
Crop Improvement ◽  
Field Trials ◽  
Growth And Yield ◽  
Wild Type ◽  
Inorganic N ◽  
Master Regulator ◽  
Nitrogen Use ◽  
Use Efficiency ◽  
N Use

AbstractNitrogen (N) is one of the key essential macronutrients that affects rice growth and yield. Inorganic N fertilizers are excessively used to boost yield and generate serious collateral environmental pollution. Therefore, improving crop N use efficiency (NUE) is highly desirable and has been a major endeavor in crop improvement. However, only a few regulators have been identified that can be used to improve NUE in rice to date. Here we show that the NIN-like protein OsNLP4 significantly improves the rice NUE and yield. Field trials consistently showed that loss-of-OsNLP4 dramatically reduced yield and NUE compared with wild type under different N regimes. In contrast, the OsNLP4 overexpression lines remarkably increased yield by 30% and NUE by 47% under moderate N level compared with wild type. Transcriptomic analyses revealed that OsNLP4 orchestrates the expression of a majority of known N uptake, assimilation and signaling genes by directly binding to the nitrate-responsive cis-element in their promoters to regulate their expression. Moreover, overexpression of OsNLP4 can recover the phenotype of Arabidopsis nlp7 mutant and enhance its biomass. Our results demonstrate that OsNLP4 is a master regulator of NUE in rice and sheds light on crop NUE improvement.

scholarly journals Do plants use root-derived proteases to promote the uptake of soil organic nitrogen?

2020 ◽  
Vol 456 (1-2) ◽  
pp. 355-367
Author(s):  
Lucy M. Greenfield ◽  
Paul W. Hill ◽  
Eric Paterson ◽  
Elizabeth M. Baggs ◽  
Davey L. Jones
Keyword(s):  
Protease Activity ◽  
Organic Nitrogen ◽  
N Uptake ◽  
Root Surface ◽  
Organic N ◽  
Soil Organic Nitrogen ◽  
Poor Access ◽  
N Deficiency ◽  
Almost All ◽  
Soil Protein

Abstract Aims The capacity of plant roots to directly acquire organic nitrogen (N) in the form of oligopeptides and amino acids from soil is well established. However, plants have poor access to protein, the central reservoir of soil organic N. Our question is: do plants actively secrete proteases to enhance the breakdown of soil protein or are they functionally reliant on soil microorganisms to undertake this role? Methods Growing maize and wheat under sterile hydroponic conditions with and without inorganic N, we measured protease activity on the root surface (root-bound proteases) or exogenously in the solution (free proteases). We compared root protease activities to the rhizosphere microbial community to estimate the ecological significance of root-derived proteases. Results We found little evidence for the secretion of free proteases, with almost all protease activity associated with the root surface. Root protease activity was not stimulated under N deficiency. Our findings suggest that cereal roots contribute one-fifth of rhizosphere protease activity. Conclusions Our results indicate that plant N uptake is only functionally significant when soil protein is in direct contact with root surfaces. The lack of protease upregulation under N deficiency suggests that root protease activity is unrelated to enhanced soil N capture.

Aboveground biomass and nitrogen nutrition in a chronosequence of pristine Dahurian Larix stands in eastern Siberia

1995 ◽  
Vol 25 (6) ◽  
pp. 943-960 ◽  
Author(s):  
E.-D. Schulze ◽  
W. Schulze ◽  
H. Koch ◽  
A. Arneth ◽  
G. Bauer ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Forest Type ◽  
Nitrogen Nutrition ◽  
Carbon Accumulation ◽  
Eastern Siberia ◽  
Available N ◽  
N Nutrition ◽  
N Cycle ◽  
Fire Cycle ◽  
N Pool

Measurements of aboveground biomass and nitrogen (N) nutrition were made during July 1993 in 50-, 130-, and 380-year-old stands of Larixgmelinii (Rupr.) Rupr. in eastern Siberia. Constituting six forest types based on understorey plants, the stands were representative of vegetation throughout the Yakutsk region. Average tree height, diameter, and density ranged from 2 m, 23 mm, and 50 800 stems/ha in the 50-year-old stand to 11 m, 160 mm, and 600 stems/ha in the oldest stand. Aboveground biomass in the 50-year-old stand was 4.4 kg•m−2, and the aboveground N pool was 1.1 mol•m−2. This was slightly higher than the N pool in a 125-year-old stand with a Ledum understorey (1.0 mol•m−2), despite its higher biomass (7.2 kg•m−2). The highest observed aboveground biomass in a 125-year-old stand (characterized by the N2-fixing understorey plant Alnasterfruticosa) reached 12.0 kg•m−2, but the corresponding N pool was only 1.6 mol•m−2. In the oldest stand, aboveground biomass was 8.9 kg•m−2 and the N pool was 1.1 mol•m−2. There was thus a relatively constant quantity of N in the aboveground biomass of stands differing in age by almost 400 years. We postulate that N sets a limit on carbon accumulation in this boreal forest type. Trees were extremely slow growing, and there was essentially no aboveground biomass accumulation between the ages of 130 and 380 years because of a lack of available N. This conclusion was supported by graphical analysis indicating that the self-thinning process in our stands was not governed by the availability of radiation according to allometric theory. Much of the available N was used in the production of tree stems where 86% of the aboveground N (and 96% of aboveground biomass) was immobilized in the oldest stand. N in wood of the old stand exceeded the N pool in the litter layer and was 20% of the N pool in the Ah horizon. The processes of carbon and N partitioning were further explored by the estimation of carbon and N fluxes during three periods of forest development. We calculated a loss of ecosystem N during the period of self-thinning, while in the mature stands the N cycle appeared to be very tight. The immobilized N is returned from the wood into a plant-available form only by a recurrent fire cycle, which regenerates the N cycle. Thus fire is an essential component for the persistence of the L. gmelinii forest.

scholarly journals Yield, Nitrogen Dynamics, and Fertilizer Use Efficiency in Machine-harvested Cucumber

HortScience ◽  
2009 ◽  
Vol 44 (6) ◽  
pp. 1712-1718 ◽  
Author(s):  
Laura L. Van Eerd ◽  
Kelsey A. O'Reilly
Keyword(s):  
N Uptake ◽  
Growing Season ◽  
Control Treatment ◽  
Yield Response ◽  
N Recovery ◽  
Fertilizer N ◽  
N Budget ◽  
Available N ◽  
N Removal ◽  
Use Efficiency

The increase in fertilizer costs as well as environmental concerns has stimulated growers to re-evaluate their fertilizer applications to optimize nitrogen use efficiency (NUE) while maintaining crop yields and minimizing N losses. With these objectives, field trials were conducted at seven sites with five N rates (0 to 220 kg N/ha) of ammonium-nitrate applied preplant broadcast and incorporated as well as a split application treatment of 65 + 45 kg N/ha. In three contrasting years (i.e., cool/wet versus warm/dry versus average), N treatment had no observable effect on grade size distribution or brine quality. Based on the zero N control treatment, the limited yield response to fertilizer N was the result of sufficient plant-available N over the growing season. In the N budget, there was no difference between N treatments in crop N removal, but there was a positive linear relationship between N applied and the quantity of N in crop residue as well as in the soil after harvest. As expected, apparent fertilizer N recovery and N uptake efficiency were lower at 220 versus 110 kg N/ha applied preplant or split. The preplant and split applications of 110 kg N/ha were not different in yield, overall N budget, or NUE. Considering the short growing season, planting into warm soils, and the generally productive, nonresponsive soils in the region, growers should consider reducing or eliminating fertilizer N applications in machine-harvested cucumber.

scholarly journals Interactions between uptake of amino acids and inorganic nitrogen in wheat plants

2011 ◽  
Vol 8 (6) ◽  
pp. 11311-11335 ◽  
Author(s):  
E. Gioseffi ◽  
A. de Neergaard ◽  
J. K. Schjoerring
Keyword(s):  
Amino Acids ◽  
Nutrient Solution ◽  
Inorganic Nitrogen ◽  
N Uptake ◽  
Organic N ◽  
Arable Soils ◽  
Inorganic N ◽  
N Losses ◽  
Total N ◽  
N Source

Abstract. Soil-borne amino acids may constitute a nitrogen (N) source for plants in various terrestrial ecosystems but their importance for total N nutrition is unclear, particularly in nutrient-rich arable soils. One reason for this uncertainty is lack of information on how the absorption of amino acids by plant roots is affected by the simultaneous presence of inorganic N forms. The objective of the present study was to study absorption of glycine (Gly) and glutamine (Gln) by wheat roots and their interactions with nitrate (NO3–) and (NH4+) during uptake. The underlying hypothesis was that amino acids, when present in nutrient solution together with inorganic N, may lead to down-regulation of the inorganic N uptake. Amino acids were enriched with double-labelled 15N and 13C, while NO3– and NH4+ acquisition was determined by their rate of removal from the nutrient solution surrounding the roots. The uptake rates of NO3– and NH4+ did not differ from each other and were about twice as high as the uptake rate of organic N when the different N forms were supplied separately in concentrations of 2 mM. Nevertheless, replacement of 50 % of the inorganic N with organic N was able to restore the N uptake to the same level as that in the presence of only inorganic N. Co-provision of NO3– did not affect glycine uptake, while the presence of glycine down-regulated NO3– uptake. The ratio between 13C and 15N were lower in shoots than in roots and also lower than the theoretical values, reflecting higher C losses via respiratory processes compared to N losses. It is concluded that organic N can constitute a significant N-source for wheat plants and that there is an interaction between the uptake of inorganic and organic nitrogen.

scholarly journals Nitrogen Uptake and Use Efficiency in Sweet Basil Production under Low Tunnels

HortScience ◽  
2020 ◽  
Vol 55 (4) ◽  
pp. 429-435 ◽  
Author(s):  
Tej P. Acharya ◽  
Mark S. Reiter ◽  
Greg Welbaum ◽  
Ramón A. Arancibia
Keyword(s):  
Open Field ◽  
N Uptake ◽  
Dry Weight ◽  
N Fertilizer ◽  
Plant N Uptake ◽  
Available N ◽  
Sweet Basil ◽  
Total Plant ◽  
Use Efficiency ◽  
Low Tunnels

Low tunnels (LTs) enhance vegetative growth and production in comparison with open field, but it is not known whether nitrogen (N) requirements and use efficiency increase or decrease for optimal crop performance. Therefore, the purpose of this study was to determine differences in N requirement, uptake, and use efficiency in basil grown under LTs compared with open field. The experimental design each year was a split plot with four replications. The main effect (plots) was N fertilizer application rate (0, 37, 74, 111, 148, and 185 kg·ha−1) and the secondary effect (subplots) was production system (LTs covered with spun-bonded rowcover vs. open field). Plant height and stem diameter were greater under LT than open field; however, they were unaffected by N fertilizer rate. Total fresh and dry weight increased with LT by 61% and 58% and by 50% and 48% in 2017 and 2018, respectively. Optimum N rates for fresh weight (98% of peak yield) were 124 and 104 kg·ha−1 N under LT and open field, respectively. Leaf N concentration decreased under LT, but total plant N uptake increased because of increased dry weight. Without fertilization, soil available N use efficiency (SNUE) for dry weight increased by 45% and 66% in 2017 and 2018, respectively. Mixed results were obtained for N fertilizer use efficiency (NFUE) in response to N rate. In conclusion, LT increased summer production of sweet basil, total plant N uptake, and SNUE.

Nitrogen Utilization of Selected Cropping Systems in the U.S. Northeast: I. Dry Matter Yield, N Uptake, Apparent N Recovery, and N Use Efficiency

1995 ◽  
Vol 87 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Karl Guillard ◽  
Gary F. Griffin ◽  
Derek W. Allinson ◽  
M. Moosa Rafey ◽  
William R. Yamartino ◽  
...  
Keyword(s):  
Dry Matter ◽  
Cropping Systems ◽  
N Uptake ◽  
Nitrogen Utilization ◽  
N Recovery ◽  
Dry Matter Yield ◽  
Use Efficiency ◽  
Apparent N Recovery ◽  
N Use ◽  
The U.S

Use of residual fertiliser 15N in soil for isotope dilution estimates of N2 fixation by grain legumes

1998 ◽  
Vol 49 (5) ◽  
pp. 821 ◽  
Author(s):  
C. J. Pilbeam ◽  
H. C. Harris ◽  
R. S. Swift ◽  
A. M. McNeill
Keyword(s):  
Isotope Dilution ◽  
Soil Depth ◽  
N Uptake ◽  
The Other ◽  
Isotope Dilution Method ◽  
Dilution Method ◽  
N Fixation ◽  
Available N ◽  
15N Abundance ◽  
N Pool

Estimates of the proportion of nitrogen (N) derived from the atmosphere (pNatm) by chickpea and lentil in the alternate phase of a cereal-legume 2-year rotation, for each of 3 seasons (1993, 1994, and 1995) in northern Syria, were obtained from isotope dilution methodology using residual fertiliser 15N in the soil (IDres). The 15N had been immobilised, during the year antecedent to the legume, from 15N-enriched fertiliser which had been applied at sowing to wheat in the cereal phase of the rotation at 30 kg N/ha. For lentil in 1994, and for chickpea in 1993 and 1994, the IDres estimates of pNatm were compared with those obtained by using the classical 15N isotope dilution method (ID) where 15N-enriched fertiliser (either 30 or 10 kg N/ha) was added at sowing to both the legume and non-fixing reference crops. Estimates of pNatm for 1994 from the 2 methodological approaches were significantly (P < 0 ·01) different for lentil, with ID resulting in a higher estimate than IDres (0·92 v. 0·85). For chickpea in the same season (1994) the IDres estimate was significantly higher than the ID estimate (0· 88 v. 0·78) at 30 kgN/ha because the N fertiliser inhibited biological N fixation (BNF). However, using a lower fertiliser rate (10 kg N/ha) for ID the estimate of pNatm obtained for chickpea in 1994 was 0·91, which was slightly higher than the IDres estimate. Proportional reliance on BNF was estimated to be greater in spring than at harvest for both lentil and chickpea. The estimates of p Natm obtained at harvest were greatest (>0·82) for both crops in 1994 and less, but similar, for both crops (0·64-0·79) in the other 2 seasons (1993 and 1995). Although substantial amounts of residual fertiliser N were present in the soil, only a small proportion of the original fertiliser N added (<5%) was utilised by plant uptake plus any losses in the residual year, indicative of a slow remineralisation rate for the immobilised labelled N. Nevertheless, the crops in the residual year were suciently enriched to allow for estimation of pNatm. The 15N abundance, at harvest, of wheat shoots from the 15N IDres method was similar to that of the soil nitrate and ammonium pools, suggesting that plant N uptake through the season had been from an N pool of reasonably constant enrichment. This was in contrast to wheat receiving 15N-labelled fertiliser at sowing, where the shoots at harvest had a higher 15N abundance than the plant-available N pool, indicating a declining15N enrichment of plant-available N in the soil through the season. Furthermore, variability in the 15N abundance of plant-available N with soil depth was also demonstrated to be greater where the 15N IDres method was used, for ammonium N at least. These differences in 15N enrichment patterns of the plant-available N pool for the 2 methods resulted in significantly different estimates for pNatm of lentil in 1994 but for all the other comparisons there were no major differences between estimates obtained using either ID or IDres.

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